Contact bridging connector utilizing electrically conductive fluid



March 24, 1970 l. APPLET ON 3,503,034

CONTACT BRIDGING N OR UT ZING ELEGTRICALLY COND IVE F D 3 Sheets-Sheet 1 Filed June 7, 1967 Ill Ill

INVENTOR ARTHUR LAPPLETON March 24, 1970 A. 1. APPLETON 3,503,034

CONTACT BRIDGING CONNECTOR UTILIZING ELEGTRICALLY CONDUCTIVE FLUID 4 Filed June '7, 1967 3 Sheets-Sheet 2 am 5 167 4 5 3 55 '53 47 73 59 I 5 llilllllllll K F069 H m 2 h INVENTOR ARTHui LAPPLE'roN Ho b 'fl/s zL waemgusv'mau March 24, 970 A. I. APPLETON 3,503,034

CONTACT BRIDGING NE OR UTILIZING ELECTRICALLY D IVE FLUID Filed June 7, 1967 3 Sheets-Sheet 5 INVENTOR Ae'rHuR I. APPL new United States Patent 3,503,034 CONTACT BRIDGING CONNECTOR UTILIZING ELECTRICALLY CONDUCTIVE FLUID Arthur I. Appleton, Northbrook, Ill., assignor to Appleton Electric Company, Chicago, III., a corporation of Illinois Filed June 7, 1967, Ser. No. 644,147 Int. Cl. H01k 11/02 U.S. Cl. 339-61 8 Claims ABSTRACT OF THE DISCLOSURE A bridging connector comprising an elastomeric body having one or more cavities, each partially filled with mercury. A pair of small openings lead to opposite ends of each cavity for receiving a pair of male contacts. When the contacts are inserted into a cavity through its openings, an electric path is established between them through the mercury. There is also disclosed a multi-contact electrical connector incorporating a bridging connector of the type described.

BACKGROUND OF THE INVENTION The present invention relates generally to the field of electrical connectors and more specifically to a novel bridging connector which is of particular, although not exclusive, use in making detachable connections in multiconductor power or control cables.

OBJECTS OF THE INVENTION A primary object is to provide a bridging connector which is simple to assemble yet durable and shock and break resistant.

It is another object to provide a bridging connector wherein a pool of electrically conducting fluid is used to bridge a pair of male contacts and wherein the conducting fluid is retained without the use of seals.

Another object is to minimize voids in the conductive fluid between the contacts and to this without causing fluid to escape from the connector. It is a related object to prevent escape of fluid from the bridging connector when one contact is inserted therein before the other.

A further object of the invention is the provision of a bridging connector assembly whereby a plurality of pairs of opposed contacts are electrically interconnected through individual pools of conductive fluid held captive within the connector without the use of special seals.

DESCRIPTION OF THE DRAWINGS The objects of the invention thus generally set forth, together with other objects and ancillary advantages are attained by the construction and arrangement shown by way of illustration of the accompanying drawings in which:

FIGURE 1 is a side view in cross-section of a bridging connector embodying the invention with a pair of opposed male contacts prior to their insertion into the connector;

FIG. 2 is a cross-section along lines 2-2 of FIG. 1;

FIG. 3 is a cut away side view of the connector of FIG. 1;

FIG. 3 is a cut away side view of the connector of FIG. 1, but with one of the male contacts inserted there in;

FIG. 4 is a cross-section along lines 44 of FIG. 3;

FIG. 5 is a cut away side view of the connector of FIG. 1 with both of the male contacts inserted therein;

FIG. 6 is a cross-section along lines 6-6 of FIG. 5;

FIG. 7 is a partially cut away side view of an illustrative connector incorporating the bridging connector of the present invention, with the two major members of the illustrative connector facing one another prior to their engagement;

FIG. 8 is a partially cut away side view of the illustrative connector of FIG. 7, but with the two major members interfitted;

FIG. 9 is a cut away side view of the bridging connector incorporated in the illustrative connector of FIGS. 7 and 8;

FIG. 10 is a cross-section along lines 1010 of FIG. 9 showing the location of chambers containing conductive liquid and the approximate amount of liquid in the chambers prior to insertion of male conductors into the chambers;

FIG. 11 is an end view of the bridging connector of FIG. 9; and

FIG. 12 is a cross-section of a modified multi-chamber bridging connector which is suitable for incorporation into the connector of FIGS. 7 and 8.

While the invention is susceptible of various modifications and alternative constructions, certain illustrative embodiments have been shown in the drawings and will be described below in considerable detail. It should be understood, however, that there is no intention to limit the invention to the specific forms or modes disclosed but, on the contrary, the intention is to cover all modifications, alternatives, and equivalents falling within the spirit and scope of the invention.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT Referring more particularly to FIGS. 1 through 6, there is shown, in its most simple form, a bridging connector 11 incorporating features of the invention for establishing electrical contact between a pair of male pintype connectors 13 and 15. The bridging connector 11, as shown in FIGS. 1 through 6, comprises a body 17 of rubbery, electrically non-conductive material such as a synthetic elastomer. Within the body 17 is a chamber 19 containing a pool 21 of electrically conductive fluid such as mercury. An electrical path is established between the male connectors 13 and 15 through the pool of mercury by providing a pair of spaced openings 23 and 25 leading through the body 17 to the cavity 19 and the conductive liquid 21 within. The relative disposition of the openings 23 and 25 will depend upon the desired location of the conductors 13 and 15. In the illustrative embodiment of FIGS. 1 through 6 the conductors 13 and 15 are shown as being axially aligned. Consequently, the openings 23 and 25 are shown as aligned openings extending from opposite ends of the body 17 into the chamber 19 In accordance with an important feature of the invention, each of the openings 23 and 25 has a smaller crosssectional area than the contact which it is to receive. As a result, as best seen in FIGS. 3 and 5, when a contact is inserted into its associated opening, the opening expands because of the elasticity of the material of which the body 17 is made, and a fluid-tight seal is established between contact and opening. To define the extent of insertion of the male connectors 13 and 15 into their respective openings 23 and 25, they are provided with stop surfaces, here shown as having the form of flared skirts 27 and 29. In order to engage the respective stop surfaces 27 and 29 snugly upon full insertion of the pins 13 and 15, the openings 23 and 25 are counter-sunk at their outer ends 31 and 33.

In accordance with another significant feature of the invention, the amount of mercury 21 placed Within the chamber 19 is so chosen as to prevent escape of the fluid through one of the openings when a contact is inserted into the other such opening, as in FIG. 3. In carrying out this aspect of the invention the volume of the pool of conductive fluid 21 is made sufficiently less than the volume of the chamber 19 so that even when one of the male contacts is inserted into its associated opening the total volume of the pool of conductive fluid 21 and the volume of liquid displaced by the portion of the pin extending into the fluid is still less than the volume of the chamber, as shown in FIG. 3. As a result, when one of the male contacts is inserted in the bridging connector 11, it will not cause escape through the other opening.

According to yet another feature of the invention, the volume of conductive fluid 21 is chosen to be less than the volume of the chamber 19 by a sufliciently small amount so that when both of the male conductors are inserted into the conducitve fluid 21 through their respective openings 23 and 25, the total volume of the fluid, when added to the volume of fluid displaced by the terminal portions of the pins 13 and 15 extending into the fluid, exceeds the normal volume of the chamber 19, causing the flexible walls of the connector body 17 to bulge, as shown at A and B. This assures that the chamber is completely filled with conductive fluid, eliminating the possibility of interruptions in the flow of current between the conductors 13 and 15 through the fluid 21 and yet, by virtue of the ability of the resilient bridging conductor body 17 to bulge, the tendency of fluid to escape between the conductors 13 and 15 and the walls of the openings 23 and 25 is greatly reduced.

It should be noted that the precaution of so proportioning the volume of conductive fluid 21 that the chamber 19 will not be completely filled when only one of the contacts 13 or 15 is inserted into the chamber 19 may be dispensed with if it is known that both of the contacts 13 and 15 will be inserted into the bridging connector 11 at the same time, as in FIG. 5. Similarly, if the connector is to be used under conditions in which the presence of small air bubbles within the chamber would not cause interruption of the electric path through the fluid in the chamber, then the chamber need not be filled to the point where its walls bulge when both contacts are inserted.

An illustrative connector wherein the bridging connector of the subject invention may be advantageously employed is shown in FIGS. 7 and 8. The connector is of the type which is the subject of application Ser. No. 373,789 by the inventor of the present invention, issued May 30, 1967 as Patent No. 3,323,096. The connector 20 of FIGS. 7 and 8 is designed to connect corresponding, opposed pairs of electrical conductors 33 and 35, and comprises a plug 37 and a receptacle 39. The plug 37 includes a tubular body 41 and a retainer nut 43 which engages an external flange 45 on the plug body. An extension sleeve 47 (shown partially broken away) is attached to the outer end of the plug body. The receptacle 39, on the other hand, comprises a tubular body 49 and an external mounting flange 51 optionally provided with a sealing gasket 53. The receptacle body 49 is adapted to receive telescopically the inner end portion of the plug body 41 when the connector is assembled, and is provided with external threads 55 engageable by the plug retainer nut 43. One or more upstanding ribs 57 on the plug body engage corresponding grooves 59 in the main bore of the receptacle body properly to orient plug and receptacle.

The connector 31 includes two sets of opposed male contacts 61, one in the plug and the other in the receptacle. To simplify illustration, FIGS. 7 and 8 show a cooperating pair of the contacts 61, one from each set, along with their respectively associated conductors 33 and 35. Since the contacts and the means for holding them are substantially identical in both the plug and receptacle, a detailed description of such an arrangement, here the plug, will suflice for both.

Contacts 61 of the plug 37 are retained in a contact holder 63 of non-conductive material comprising, in the illustrative connector, a pair of rigid non-conductive discs 65, 67 separated by a disc 69 of resilient non-conductive material such as silicon rubber. Each contact 61 is retained against pull-out by means of medially located spring clips 71 which engage an internal shoulder 48 in the disc 65. A longitudinal rib 73 in the interior of the plug body and a corresponding common groove (not shown) in the outer peripheries of the holder elements 65, 67, and 69 orient the contact holder 63 and its contacts with respect to the plug 37. The contact holder 63 is seated against a stop shoulder 75 in the plug body and is retained in place by means of a washer 77 interposed between the outer end of the plug body and the shoulder 79 adjacent the inner end of the plug extension sleeve 47.

The contacts and holding means in the receptacle 39, as already indicated, are similar to those of the plugs 24. Thus, a contact holder 63 is seated in the receptacle body against a stop shoulder 81 and is secured in place by a washer 83 carried by a retainer nut 85 on the end of the receptacle remote from the plug. The contact holder and receptacle body also include polarizing means similar to those associated with the plug 37.

In accordance with the invention, a positive bridging connection is established through an individual pool of conductive fluid between each pair of opposed contacts respectively associated with the plug and receptacle as an incident to assembling the plug and receptacle together. This is accomplished by the use of a multi-chamber bridging connector 87 incorporating one or more of the inventive features of the basic bridging connector of FIGS. 1 through 6. Thus, there are provided within a body of elastomeric non-conductive material a plurality of individual chambers with a pair of opposed openings extending from each chamber through the body to admit a pair of opposed, male contacts into the chamber. Selected ones, or all, of the chambers contain pools of conductive fluid for electrically interconnecting selected pairs, or all pairs, of contacts in the electrical connector.

Referring more specifically to the drawings, in particular to FIGS. 7 through 11, the connector 87 has a cylindrical body 89 of resilient non-conductive material, such as a synthetic elastomer, with a plurality of chambers 91, each having at its opposite end openings 93 in registry with corresponding pairs of contacts of the plug and receptacle. The openings are outwardly flared to mate with stop surfaces on the contacts of FIGS. 1 through 6. The bridging connector body 89 has external polarizing means such as the longitudinal slot 97 for engaging aligned longitudinal ribs 99 on the bodies of the plug and receptacle.

The bridging connector 87 is attached to the receptacle 39 which in the illustrative connector is assumed to be the one carrying electrically live conductors. A suitable means for attaching the bridging connector to the receptacle 39 is a mounting screw 101 which extends through a central opening in the body of the connector and which threadably engages a tapped hole 103 in a plug 105 situated in the face of the receptacle contact holder 63. A similar tapped hole and plug are provided in the face of the plug contact holder 63, and the bridging connector may be secured to the plug by simply reversing the screw 10 1.

As indicated earlier in connection with FIG. 3, when it is contemplated that one conductor will be inserted in the conductive fluid before the other conductor is so inserted, the volume of fluid relative to the volume of the chamber will be chosen to be such that with only one of the contacts inserted, the chamber is not completely filled, thus preventing escape of fluid through the unobstructed open ing. This relationship is shown in FIG. 7.

It was also noted in connection with FIG. 5 that, to insure a continuous electric path between the contacts in' serted in the conductive fluid, the chamber with the pins inserted therein would be over-filled, but any excessive pressure in the fluid being relieved by the bulging of the rubbery chamber walls thus preventing back-up and escape of the fluid through the openings. This same feature is seen in FIG. 8. To permit the walls of the connector to expand freely, a shallow peripheral groove 107 is provided on the inner surface of the plug body 41 around the set of chambers within the bridging connector. For the same purpose, the opening within the bridging conductor body 89 through which the screw 101 passes is enlarged so as to permit inward bulging of the inside walls of the bridging connector chambers, as at 109. This bulging may be clearly seen in FIG. 8. A hollow cylindrical rivet 111 within the opening maintains the screw 101 centered within the opening and also provides a firm seating face in the relatively sift body of the connector 87.

FIG. 12 shows a modification of the multi-chamber bridging connector of FIGS. 7 through 11, particularly suitable where a large number of contact pairs are to be bridged. The bridging connector 113 of FIG. 12 features two concentric rows of chambers 115 and 117, each chamber partially filled with conductive fluid. The chambers and openings of the bridging connector 113 are configured in the same way as their counterparts in FIGS. 7 through 11, the principal difference lying in the provision of additional pressure relief chambers 119 and 121 between the outer and inner sets of fluid-bearing chambers 115 and 117. By virtue of these pressure-relief chambers, the inwardly facing walls of the outer set of fluid-bearing chambers 115 are permitted to bulge inwardly, and similarly the walls of the inner set of fluidbearing chambers 117 nearest the outside of the bridging connector 113 are permitted to bulge outwardly. It will 'be seen that more than two concentric rows of fluidbearing chambers may be provided so long as sufficient pressure relief chambers are incorporated between successive rows of chambers.

From the above it will be seen that there has been brought to the electrical connector art a novel and highly useful bridging connector. By using a conductive fluid as the bridging element, contact life is extended, and assembly of the bridging connector, especially where designed to accommodate a plurality of pairs of contacts, is greatly simplified. Once the connector body is molded, conductive fluid is simply injected in all, or selected ones, of the chambers formed therein. If less than all chambers are to be filled, the pattern of chambers filled can be readily controlled by automatic machinery.

I claim as my invention:

1. An electrical connector comprising in combination,

(a) a body of elastomeric, electrically non-conductive material,

(b) means defining a chamber within said body containing electrically conductive fluid,

(c) means defining a pair of spaced openings, each of a cross-sectional area, leading through said body to said chamber and, a pair of electrically conductive contacts dimensioned for insertion into said chamber through respective ones of said openings, the portion of said contacts extending into said chamber when the contacts are fully inserted through said openings having a volume exceeding whatever volume of the chamber is left unfilled by said fluid when the contacts are retracted so that with the contacts fully inserted, the chamber is over-filled and its walls bulge.

2. The bridging connector of claim 1 wherein the volume of the end portion of one contact extending into said chamber when said one contact is fully inserted through its associated opening is less than the volume of the chamber left unfilled by said fluid when both contacts are retracted, so that when said one contact alone is inserted, the chamber is not over-filled and fluid does not escape through the unobstructed opening.

3. The electrical connector of claim 1 wherein said body material is a synthetic elastomer, said fluid is mercury, and said openings enter said chamber at opposite "ends.

4. The bridging connector of claim. 1 wherein each of said contacts has a larger cross-sectional area than the opening through which it is inserted thereby expanding and sealingly engaging said opening. 1

5. In a multiconductor electrical connector having first and second members with opposed sets of contacts thereon, an improved bridge assembly comprising in combination,

(a) a body of resilient, electrically non-conductive material,

(b) means defining a plurality of individual chambers within said body,

(c) means defining a pair of opposed openings extending from each said chamber through said body to admit a pair of opposed contacts into said chamber,

(d) pools of conductive fluid in at least some of said chambers for electrically interconnecting selected pairs of said contacts, said fluid within and contact portions extending into each fluid-containing chamber occupying a total volume exceeding the normal volume of the chamber so that its walls bulge when both contacts are inserted therein.

6. The bridge assembly of claim 5 wherein the total volume of the fluid within and one of the contact p0rtions extending into each fluid-containing chamber is less than the normal volume of the chamber so that fluid is not forced out through one of a pair of chamberopenings when a contact is first inserted into the other opening of the pair.

7. The bridge assembly of claim 5 wherein said body material is a synthetic elastomer and said fluid is mercury.

8. The bridge assembly of claim 5 wherein each of said openings has a smaller cross-sectional area than the contact which it admits.

References Cited UNITED STATES PATENTS 2,560,940 7/1951 Findley.

3,127,230 3/1964 Marquis et al. 339-118 3,158,420 11/1964 Olson et al 339-96 FOREIGN PATENTS 1,143,246 4/1957 France.

OTHER REFERENCES William Hyde, Field Wire Connector 658, 0.6. 918, May 1952.

MARVIN A. CHAMPION, Primary Examiner JOSEPH H. MCGLYNN, Assistant Examiner US. Cl. X.R. 339118 

